first ride with new jetting...need some advice

jtm994

Member
Dec 4, 2006
125
0
Last saturday i took the KTM out for the day on some trail and open feilds. I am in the process of trying to find the right jetting for the bike and my riding style. The bike is a 05 250SX and the jetting is 70 main, 42 PJ, 1 1/2 AS, and JD blue middle clip running 44:1 redline oil. When i fire the bike up it smokes so much until i ride it around for a few secs and then it clears up. When going through the woods i noticed when i was coming up on a trun and i pull the cluch and rev the engine it hesitates to rev. Also when the bike is cold it idels perfect but after it warms up it doesnt want to idel, it cuts out. Besides those things the bike ran good. There is a little spooge and very little smoke once warmed up. I pulled the plug and the entire plug was black (running rich i am guessing). What do you guys think?
 

HiG4s

~SPONSOR~
Mar 7, 2001
1,311
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jtm994 said:
Last saturday i took the KTM out for the day on some trail and open feilds. I am in the process of trying to find the right jetting for the bike and my riding style. The bike is a 05 250SX and the jetting is 70 main, 42 PJ, 1 1/2 AS, and JD blue middle clip running 44:1 redline oil. When i fire the bike up it smokes so much until i ride it around for a few secs and then it clears up. When going through the woods i noticed when i was coming up on a trun and i pull the cluch and rev the engine it hesitates to rev. Also when the bike is cold it idels perfect but after it warms up it doesnt want to idel, it cuts out. Besides those things the bike ran good. There is a little spooge and very little smoke once warmed up. I pulled the plug and the entire plug was black (running rich i am guessing). What do you guys think?


I have an 03 so not sure if it is the same, but I'd say you need a 40 PJ and maybe drop the needle one slot.

also,, all motocross bikes have such light flywheels and agressive timing, many brands do not idle well. My old Husqvarna CR125 didn't idle well ever , my sons yz125 idled fair, my old KTM250exc (heavier flywheel) idled fine.. my 03 sx only idled fair, but I just added a 12 oz flywheel weight. I have not got it out yet so not sure how much difference it makes.
 
Last edited:

CR Swade

~SPONSOR~
Jan 18, 2001
1,764
5
On my 05 250 I ran a 40 pilot, 165 main and the JD red needle using the clip to adjust for temp changes ( I usually ran around the 2nd clip spot). The blue needle was just too rich for me even in the winter. My riding elevation was usually around 600-2000 ft. For elevation riding above 8000ft I used the 35 pilot, w/ a 160 main
 
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